<template>
  <div id="root">
    <div class="todo-container">
      <div class="todo-wrap">
				<!-- 头部结构 -->
        <Header @add-todo="addTodo"/>
				<!-- 列表结构 -->
        <List v-show="todos.length" :todos="todos" :checkTodo="checkTodo" :deleteTodo="deleteTodo"/>
				<!-- 底部结构 -->
        <Footer :todos="todos" :checkAll="checkAll" :clearAllDone="clearAllDone" v-show="todos.length"/>
      </div>
    </div>
  </div>
</template>

<script>
	import Header from './components/Header'
	import List from './components/List'
	import Footer from './components/Footer'

	export default {
		name: "App",
		components:{Header,List,Footer},
		data() {
			return {
				todos:JSON.parse(localStorage.getItem('todos')) || []
			}
		},
		watch:{
			todos:{
				deep:true,
				handler(val){
					localStorage.setItem('todos',JSON.stringify(val))
				}
			}
		},
		methods: {
			//用于勾选or取消勾选一个todo项
			checkTodo(id){
				//寻找到当前操作的那个todo对象
				const findResult = this.todos.find(todo => todo.id === id)
				//修改该对象身上的done值
				findResult.done = !findResult.done
			},
			//用于删除一个todo
			deleteTodo(id){
				//寻找到当前操作的那个todo对象的索引值
				const index = this.todos.findIndex(todo => todo.id === id)
				//通过索引值删除
				this.todos.splice(index,1)
			},
			//用于添加一个todo
			addTodo(todoObj){
				this.todos.unshift(todoObj)
			},
			//用于全选or全不选
			checkAll(done){
				this.todos.forEach( todo =>todo.done = done)
			},
			//用于清除所有已完成的
			clearAllDone(){
				this.todos = this.todos.filter((todo)=>{
					return !todo.done
				})
			}
		},
	};
</script>

<style>
/*base*/
body {
  background: #fff;
}

.btn {
  display: inline-block;
  padding: 4px 12px;
  margin-bottom: 0;
  font-size: 14px;
  line-height: 20px;
  text-align: center;
  vertical-align: middle;
  cursor: pointer;
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.2),
    0 1px 2px rgba(0, 0, 0, 0.05);
  border-radius: 4px;
}

.btn-danger {
  color: #fff;
  background-color: #da4f49;
  border: 1px solid #bd362f;
}

.btn-danger:hover {
  color: #fff;
  background-color: #bd362f;
}

.btn:focus {
  outline: none;
}

.todo-container {
  width: 600px;
  margin: 0 auto;
}
.todo-container .todo-wrap {
  padding: 10px;
  border: 1px solid #ddd;
  border-radius: 5px;
}
</style>